1991019836 has 24 divisors (see below), whose sum is σ = 3823110144. Its totient is φ = 901592640.

The previous prime is 1991019827. The next prime is 1991019847. The reversal of 1991019836 is 6389101991.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 358460 + ... + 363971.

It is an arithmetic number, because the mean of its divisors is an integer number (159296256).

Almost surely, 2^1991019836 is an apocalyptic number.

It is an amenable number.

1991019836 is a deficient number, since it is larger than the sum of its proper divisors (1832090308).

1991019836 is a wasteful number, since it uses less digits than its factorization.

1991019836 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 722501 (or 722499 counting only the distinct ones).

The product of its (nonzero) digits is 104976, while the sum is 47.

The square root of 1991019836 is about 44620.8453079948. The cubic root of 1991019836 is about 1258.0325042173.

The spelling of 1991019836 in words is "one billion, nine hundred ninety-one million, nineteen thousand, eight hundred thirty-six".